Automobile generator control



March 12,1935. A, ENGER 1,994,370

AUTOMOBILE GENERATOR CONTROL Filed April 20, 3.932

Patented Ma. 12, 1935 1,994,370

UNITED STATES PATENT orrlcs AUTOMOBILE GENERATOR CONTROL Albert C.Sanger, Hamilton, Ohio Application April 20, 1932, Serial No. 606,417

2 Claims. (Cl. 171-229) This invention relates to automobile batterylead 13' forming a continuation of lead 13 is also charging apparatus inwhich the battery is grounded at 18 thus connecting the winding 12charged by means of an engine driven generacross the armature. ator, Ina shunt wound generator of the character 5 One object of the inventionis the provision which is referred to, the voltage of the gener- 5 of aregulator of sturdy and simple construction ator increases as the speedincreases. At any which will automatically maintain the battery givenspeed the generated voltage falls as the load charging current at asubstantially constant preincreases so that when the automobile headlamps determined value under various load conditions are turned on orwhen current is otherwise con- 1o of the generator, sumed by the currentconsuming parts of the Another object of the invention is the provisionautomobile or its accessories there would be very of a regulator 01' thecharacter mentioned for little current supplied for charging thebattery. use in conjunction with a shunt wound gener- If there is asubstantial amount of load required ator of the fixed brush type, andhaving provision as in night driving 0 W using an automobile forcontrolling a variable resistance connected batte y Op d radio, Overcomparatively long 15 in series with the shunt winding of thegenerstretches of time, the battery would become disator so as toautomatically maintain the gencharged. Conversely the battery chargingrate erator charging current at a substantially con- Would be oo highand Would in t s y t stant value regardless of the generator load andeffectiveness of the battery where the automobile regardless also of thegenerator speed. is operated in the daytime over comparatively 20 Afurther object of the invention is the prolarge distances. In accordancewith the present vision of a compact assembly adapted to be invention,however, means are provided for mounted adjacent the driver's locationso that automatically maintaining the battery charging it may beconnected with the generator but prorate at a substantially constantvalue regardvided at a point where it may be readily and less of thegenerator load and regardless of the 25 quickly adjusted for variationof the charging generator p d- This eans is u der the manrate of thebattery, ual control of the operator so that he can readily Otherobjects and advantages of the invention adjust the amount f Chargingrate as q dwill be apparent from the following description, AS S w inand so wn diagramthe appended claims and the accompanying matically inFig. l, 20 designates a suitable cas- 30 drawing, in which-- ing inwhich is contained a series of carbon disks Fig. 1 is a diagrammaticview of a battery forming a carbon pile resistance 21. At one endcharging system embodying the present inven of the series of disks is ametal washer 22 contion; tacting with a metal stud 23 threaded in an endFig. 2 is a. front elevation of a, unit assembly of the casing andadapted to be electrically con- 35 adapted to be mounted adjacent thedri rs 1 nected to the wire 13' which extends 'to the field cation 01'an automobile; winding of the generator. The casing 20 pref- Flg. 3 is aside elevation of the unit assembly; e y em es a easing portion 4 0fbakelite d or similar molded material and a metallic sleeve Fig. 4 is acentral sectional view of the battery member 25 which is held in placeat one end of 40 charge regulator. the portion 24 by means of a setscrew 26. The

Referring more particularly to the drawing sleeve member 25 is providedwith external by reference numerals, like numerals designating t Whereit P ojects beyond the end of the similar parts in the various views, 10designates p0rtion24, and a holding nut 27 is threaded on an'eng'inedriven battery charging generator of the sleeve member and holds the endof the cas- 45 an automobile or the like, by means of which ing securelyaga t a metallic Supporting p ate charging current is supplied to thestorage bah 29 which is grounded to the automobile frame. tery 11. Asherein shown the generator 10 is On the casing portion 24 is a Winding 0of a two-pole shunt wound device having the shunt sufliciently heavywire so as to carry the battery 60 winding 12 extending around the twopoles and charging current, this winding comprising a connected at oneend to a lead 13, the opposite number of layers of turns which creates asubend of the winding being connected to a lead 14. stantial pull on asolenoid plunger 32 provided The two brushes 15 are provided ondiametrically within the casing and at one end of the winding oppositeportions of the armature 16. One of the in alignment with the series ofthe carbon disks 65 brushes is grounded as indicated at 17 and the 21.This solenoid plunger 32 is preferably of iron or steel, coated withcopper so as to give a good electrical conducting surface and preventingthe plunger 32 from clinging to the core of the fixed magnet or fluxconducting member 25. Plunger 32 carries the current from the resistanceto the metallic sleeve member 25 which is also preferably coated withcopper. As the sleeve member 25 is grounded to the supporting plate 29it will be apparent that the carbon pile resistance which is connectedin series with the shunt field winding is grounded so that the currentmay return through the ground connection to the brush at 17.

The plunger 32 is preferably slidably received in a cylindrical socketprovided at the end of the sleeve member 25 in which there is acompression spring 34. One end of this spring bears against the plunger32 and the other end against a pin or washer member 35. Threaded in thesleeve member 25 is an adjusting stud 36 which may be turned so as tomove axially in the direction of the plunger and the carbon pileresistance. A finger operated control knob3'7 is fixed to the end of theadjusting stud so that it may be readily controlled to effect thedesired pressure of the spring, the spring serving, of course, to holdthecarbon pile resistance yieldingly under suitable pressure. The actionof the spring, however, is opposed by the solenoid action of the coiland plunger, the plunger tending to be pulled away from the carbon pileresistance in accordance with the amount of current flowing through thecoil 30. A spring 39 is preferably provided between the end of thesleeve member 25 and the control knob 3'7 so as to hold the knob 37 inany desired position of adjustment in a yielding manner.

The wire 13 which is connected to the carbon pile resistance extends toa current indicating device 40 which in turn connects to the fieldwinding 12 so that indications on the device 40 will show generally theheating effect of the field winding generator at any time. An ammeter 42is preferably provided in series with the battery 11 so as to show thebattery charging current at any time. The solenoid coil 30 is connectedto the ammeter 42 and to the lead wire 14 which extends to thegenerator. 43 designates a manual switch of any suitable character bymeans of which the load 44 may be connected. This load may be theheadlights of the automobile, the ignition coil, the radio receiving setand any other accessory to which power is supplied at any time. It willbe understood that the ordinary voltage cut-out which interrupts theconnection of the generator may be provided in the wire 14 so as toautomatically cut the generator in or out at some predetermined minimumgenerator speed.

It will now be apparent that the solenoid coil 30 carries all of thebattery charging current at all times, and automatically controls thepressure on the carbon pile resistance so as to increase or decreasetheamount of current in the field winding of the generator automatically inorder that the charging rate of the battery may be maintained. Ifthehand knob 37 has been so set as to provide for a battery chargingrate of, let us say, 4 amperes, this battery charging rate will bemaintained practically constant, although, of course, some smallvariations will occur depending upon the state of charge of the batterygenerator speed, etc. However, for all practical purposes this batterycharging rate will be maintained substantially constant regardless ofwhether the load is great or small and regardless of whether the speedis high or low so long as it is above the speed at which the cut-outbecomes eifective. Consider the condition of practically no-load at 44.The entire current flowing through the wire 14, that is the entiregenerator output, is then supplied through the winding 30 to thebattery. Under these conditions there will be a certain current flowingin the field winding and through the current indicating device 40 andthe carbon pile resistance 21. If the speed of the generator is thenincreased somewhat, the generated voltage will then increase and thecurrent flowing to the battery will then tend to be increased, but anyincrease in the battery charging current will cause the solenoid to soaifect the carbon pile as to increase its resistance and this willautomatically cut down the field current of the generator so as tomaintain the charging rate substantially constant. Let us now assumethat the headlights are turned on so that there will be a substantialflow of current required in the load circuit through the switch 43, nowclosed. Throwing on the load ordinarily would tend to decrease thegenerator voltage, and with a drop in generated voltage the batterycharging current would fall possibly to zero. Any decrease in currentthrough the winding 30, however, would very materially decrease the pullon the plunger in opposition to the spring and thus the spring would actto very considerably increase the pressure on the carbon pile resistanceso that there would be an increase in current flowing in the fieldwinding which would maintain the voltage of the generator so as tomaintain the desired flow of current through the coil 30 and to thebattery. The result is that the battery charging current is maintainedpractically constant regardless of the generator load and regardless ofthe speed of the generator except, of course, under idling conditions inwhich the automatic cut-out, if set to operate at a point below theidling speeds, would interrupt the circuit from the generator.

The automatic regulator is preferably used with a simple fixed brushshunt wound generator because a generator of that type is very simple inconstruction and economical in cost. The manual control of the controlknob 3'7 which is preferably provided adjacent the driver's locationaffords a means of readily adjusting the charging rate so that the useof a third brush type of generator is not required. However, the deviceshown in Fig. 4 may also be used in conjunction with a third brush typeof generator and will give practically uniform charging rate regardlessof the speed of the generator and, of course, for any given speed theload may be widely varied without afiecting the charging rate suppliedto the battery. The automobile could, therefore, be driven in daytimeover long trips under conditions where the external load of thegenerator is negligible and under such conditions the hand control knob37 is so set as to provide a charging rate of minimum value suflicientto take care of the starting loads on the battery. If, however, it isintended that the automobile should be so operated as to rathercontinuously require large current supply to the battery, the controlknob 37 is set to provide a suitable charging rate during the time thecar is in use and then if it is found that the battery is maintainedfully charged, of course, the charging rate can be reduced somewhat. Thebattery is therefore always maintained in a charged condition andovercharge is guarded against.

herein shown and described, for the control of the current in the shuntfield winding, the carbon pile resistance is particularly desirable asit afl'ords a satisfactory and accurate control through a wide range ofcurrent values. When the field current is greatest, the heat required tobe dissipated by the carbon pile resistance is carbon apparatus themetal which are mechanically connected to supporting plate 29.

ing the pressure on the plates of the carbon pile While stillmaintaining the entire resistance in circuit.

The battery charging regulator is constructed in front of the driver.The current indicating device which is connected in series with theshuntfield winding and identified by the nuthe operator. 50 designates asmall dash lamp which illuminates the dial of the current indimanuallyadjustable knob 37 is provided in a readily accessible position so thatthe pilot may instantly, merely by turning the knob, control the batterycharging rate so that resistance in said casing ing the engine, and thecondition of the battery charge.

While the form of apparatus herein described constitutes a preferredembodiment of the inwithout departing from the scope of the invenin theappended claims.

1. An automobile battery charging regulator of the character describedcomprising a casing, a screw adjustably threaded in one end of theeasing and projecting from the casing, a carbon pile coil in oppositionto the action of the spring.

2. An automobile battery charging regulator of the character describedcomprising a casing, a carbon pile resistance provided in one end ofsaid casing, means for conducting current to one said coil in oppositionto the action of the spring.

ALBERT C. SENGER.

